Fold a kitchen towel into quarters and set it inside a large, wide bowl. Use one hand to hold each of the
Corn Cobs (8)
in place upright atop the kitchen towel; it helps to pinch the ear at the top. With your other hand, use a chef's knife to cut off two to three rows of kernels at a time by sliding the knife down the cob. Get as close to the cob as you can. Save the cobs.
In a soup pot, quickly make a corn cob stock: cover the cobs with
Water (9 cups)
and bring to a boil. Reduce heat and simmer for 10 minutes, then remove the cobs. Set stock aside.
Return the empty pot to the stove and heat over medium heat. Add the
Unsalted Butter (1/2 cup)
. Once it has melted, add the
Yellow Onions (2)
and reduce heat to medium-low. Cook, stirring occasionally, until the onions are translucent, or blond, about 20 minutes.
As soon as the onions are tender, add the corn. Increase the heat to high and sauté just until the corn turns a brighter shade of yellow, 3-4 minutes.
Add just enough stock to cover everything, and crank up the heat to high. Save the rest of the stock in case you need to thin out the soup later. Season with
Salt (to taste)
, taste, and adjust. Bring to a boil, then simmer for 15 minutes.
If you have an immersion blender, use it to carefully blend the soup until it is puréed. If you don't have one, work carefully and quickly to purée it in batches in a blender or food processor. For a very silky texture, strain the soup one last time through a fine-mesh sieve.
Taste the soup for salt, sweetness, and acid balance. If the soup is very flatly sweet, a tiny bit of
White Balsamic Vinegar (to taste)
can help balance it out.
For the salsa, in a small bowl, combine the
Shallots (3 Tbsp)
Lime Juice (3 Tbsp)
and let sit for 15 minutes to macerate.
In a separate small bowl, combine the
Fresh Cilantro (1/4 cup)
Jalapeño Peppers (1 Tbsp)
Scallions (2 Tbsp)
Olive Oil (1/4 cup)
Salt (to taste)
Just before serving, use a slotted spoon to add the shallot (but not the lime juice, yet) to the herb oil. Stir, taste, and add lime juice as needed. Taste and adjust salt.
Serve the soup hot or chilled with salsa spooned over top. Bread on the side is never a bad idea.